Acylamidoethoxyethyl sulfosuccinate salts, methods of producing the same and froth-forming compositions containing the same

ABSTRACT

The soluble salts are powerful foaming agents with but limited emulsifying properties, however with unexpected mildness characteristics toward the tissue of the eye and skin. Preferable process conditions producing products falling within this invention include formation of the acylamidoethoxyethyl acid maleate at temperatures below about 70*C and addition of the bisulfite or sulfite moiety to the maleate at temperatures below about 70* C, preferably 60* C. The compounds of this invention lend themselves ideally as base ingredients for bubble bath formulations, hair shampoos and synthetic liquid or bar soaps. Introduction of a single ethyleneglycol linking unit into an acylamidoethyl sulfosuccinate salt yields water-soluble salts within the following formula:

United States Patent [19] Ernst et al.

[ ACYLAMIDOETHOXYETHYL SULFOSUCCINATE SALTS, METHODS OF PRODUCING THE SAME AND FROTH-FORMING COMPOSITIONS CONTAINING THE SAME [75] Inventors: Robert Ernst, Los Angeles; Eugene J. Miller, Huntington Beach, both of Calif.

[73] Assignee: Textilana Cerporation, Hawthorne,

Calif.

[22] Filed: Aug. 30, I973 [211 App]. No.: 392,976

[52] US. Cl 260/401; 260/404 [5i] Int. Cl. C07C 143/90; Cl lD 1/28 [58] Field of Search 260/401 [56] References Cited UNlTED STATES PATENTS 2,903,466 9/1959 Walling et al 260/401 Primary ExaminerElbert L. Roberts June 24, 1975 [5 7 ABSTRACT Introduction of a single ethyleneglycol linking unit into an acylamidoethyl sulfosuccinate salt yields water-soluble salts within the following formula:

The compounds of this invention lend themselves ideally as base ingredients for bubble bath formulations, hair shampoos and synthetic liquid or bar soaps.

12 Claims, No Drawings ACYLAMIDOETHOXYETHYL SULFOSUCCINATE SALTS, METHODS OF PRODUCING THE SAME AND FROTH-FORMING COMPOSITIONS CONTAINING THE SAME BACKGROUND OF THE INVENTION Surface active agents capable of producing copious foam or lather have the inherent disadvantage of removing much of the natural oil on hair and skin. Such defatting action on hair, for example, results in static electrification on combing and makes the hair fuzzy and difficult to style.

Similarly, where such frothing agents are employed in bubble bath preparation, pronounced detergent and emulsifying properties of such foamers lead to excessive drying of the skin and generally also to skin and eye irritation.

To overcome these deficiencies, emolients or conditioning agents are used as adjuvants in such personal use surfactant preparations. These may be water dispersible lipids or proteins as well as surface active amine derivatives, such as higher alkyl amphoterics, betaines, or amine oxides. The addition of these agents frequently lowers the frothing ability of the principal foaming agent used without fully curing the deficiency.

STATEMENT OF THE INVENTION We have made the surprising observation that the introduction of a single ethyleneglycol linking unit into a higher fatty acylamidoethyl sulfosuccinate salt, such as are described in German Pat. No. 1,] 15,398 by H. Praetorius, will yield powerful foaming agents, with much lower interfacial tension reducing properties and, therefore, substantially lower emulsifying and detergent properties than the textile washing compounds of the patent named above. Parallel with these physical properties is the finding that the novel compounds produce zero exposure units (no discernable irritation) on intact or abraded skin when solutions of reasonable use concentrations and even concentrations up to 40% are applied in accordance with Section 191.10, Part I of the Hazardous Substances Labeling Act. Likewise, zero score units result when the foaming agents of this invention are tested for eye irritation effects by the Draize method at concentrations up to 10% (Draize, J. l-I., Appraisal of the Safety of Chemicals in Foods, Drugs, and Cosmetics, Assoc. Food Drug Officials, U.S., Topeka, Kansas, 1959). Under conditions of this test, irritant to the eye mucosa is considered to be a substance which shows discernible opacity or ulceration of the cornea; inflammation of the iris; a diffuse, deep-crimson -red with individual vessels not easily discernible in the conjuctivae; or an obvious swelling with partial eversion of the lids. Readings are made at 24, 48 and 72 hours.

The novel surfactants which show this freedom from skin and eye irritation at and above normal use levels are the water-soluble salts that conform to the following general structure:

wherein:

R is an acyclic group having from 7 to 19 carbon atoms in an uninterrupted carbon-carbon chain.

M is selected from the group consisting of alkali metal and water-soluble salt yielding alkaline earth and A is selected from the group consisting of M, ammonia and an amine, such as the water-solubie amines or H. R may be a straight chain acyclic saturated or unsaturated C, to C radical or mixtures of such radicals, for example, as found in naturally occurring animal or vegetable oils and fats. Thus, for example, RCO may be noctanoyl, n-decanoyl, lauroyl (n-dodecanoyl), myristoyl (n-tetradecanoyl), palmitoyl (n-hexadecanoyl), stearoyl (n-octadecanoyl palmitoleoyl (n-9- hexadecenoyl), oleoyl (n-9-octadecemoyl), linoleoyl (n-9, IZ-octadecadienoyl), linolenoyl (n-9, l2, l5- octadecatrienoyl), or mixtures thereof.

In addition to the above, compounds containing the even-numbered unbranched acyl groups analogues, for example, nonanoyl, undecanoyl, tridecanoyl, etc., may be used.

However, in view of the commercial availability of mixtures of acids and esters containing the aforementioned radicals, we prefer to employ the mixtures which are thus available, for example, as present in coconut coil, palm-kernel oil, babassu oil, cohune oil, murmuric oil which contain substantial percentages of the esters of Iauric acid and myristic acid. The acyclic radicals present in such oils will be grouped under the designation cocoyl" representing the C -C radicals of the acyl groups found in the above natural oil.

In like manner, the unsaturated radicals found in oleic, linoleic or linolenic acids will be grouped as oleoyl, i.e., C

The saturated and unsaturated radicals found in animal oils and fats, such as palmitoyl, stearoyl, and oleoyl will be grouped as talloyl" (C -C When reference in this specification and the claims is made to R being C C it will be understood that it refers to a particular compound where the number of carbon atoms in R is in the range of C, to C Where, however, the R is defined as a mixture coming within the range of (C to C it will be understood that the formula so defined represents a mixture of compounds in which in each compound the R radical has a carboncarbon chain of atoms whose number is in the range of C to C In the preferred embodiment, M is selected from the group consisting of sodium, potassium and magnesium; a is selected from the group consisting of M, hydrogen, ammonia, triethanolamine, triisopropanolamine and other water soluble amines.

In order to obtain the optimum properties of high foam and low eye and skin irritation indices, it is desirable that process conditions be chosen to assure high conversion of the reagents within each step of the synthesis into the acylamidoethoxyethyl sulfosuccinate salts. The synthesis comprises three steps: formation of the acylamidoethoxyethanol; reaction with maleic anhydride to form an acylamidoethoxyethyl acid maleate; and addition of the bisulfite or sulfite moiety across the double bond of the maleate; conversion to acylamidoethoxyethyl sulfosuccinates containing from 60% to Active Matter (as hereinafter defined as MB Actives) based upon total organic solids in the reaction product may be readily achieved by the improved process given herein. Reaction products of higher purity containing higher concentrations of the aforementioned sulfosuccinate salts up to substantially may be obtained by purifying the reaction products in each stage, i.e., the acylamidoethoxyethanol and the acylamidoethoxyethyl acid maleate or the final product, i.e the sulfosuccinate. However, we have found that products of the purity obtained by the reactions as herein described are of excellent quality having the desirable high-frothing action with low emulsifiability but with the desirable mildness as is described herein. The active matter, i.e., the herein acylamidoethoxyethyl sulfosuccinate salt is referred to as M.B. Actives and is determined by methylene blue cationic titration (Epton, S.R. Trans. Faraday Soc, 44, 226,1948; Garr, T., Oliver, J., and Stubbings, W. J. Soc. Chem. Ind., Land., 67, 45, I948), Pat. 3,376,333, col. 7. In any event, process conditions, reagent purities, and reagent ratios should be such that M.B. Actives will be above about 60% and preferably a higher percent of the total organic solids as determined by extracting the dried reaction mixture with ethanol.

PREPARATION OF ACYLAMIDOETHOXYETHANOL (ACYLDIETHYLENEGLYCOL AMIDES) These amides may be prepared by reacting diethyleneglycolamine, i.e., 2-(2-aminoethoxy)ethanol with a carboxylic acid or mixture of carboxylic acids (C to C referred to above or their methyl ester or glyceride. Molar equivalents may be used but a moderate excess of the amine (up to to 10 percent over the stoichiometric requirements) will result in suitable precursors for further reactions. Such amides may be prepared by methods well known in the art to produce products containing less than 5 percent each of the unreacted C to C carboxylic acids, amine or the amine salt and will be suitable without further purification. If desired, the free amine content may be further lowered by stripping at reduced pressures (for instance at 150 to 160C at 25 to 50 mm Hg) or by washing with saline solution followed by drying.

When such amides are produced via amidation of the methyl esters, the alkali metal catalyst, such as sodium methylate, need not be removed or neutralized prior to the preparation of the maleate acid ester of these diethyleneglycolamides.

PREPARATION OF THE ACYLAMIDOETHOXYETHYL ACID MALEATE The liquid or melted aforesaid acylamidoethoxyethanol is agitated in a suitable reaction vessel while adding preferably a stoichiometric amount or up to about 1.1 times the stoichiometric amounts of maleic anhydride at such a rate as to prevent the temperature from rising above about 70C. Preferably the temperature is controlled at 60C 5C and the mixture held there for about 3 to 4 hours under agitation. Maximum conversion to the acylamidoethoxyethyl acid maleate occurs if the finished product is aged for a period of l2 hours or longer. This may be done at room (ambient) temperature, i.e., about 40C.

Employing the above procedures for production of the amide and maleate, acylamidoethoxyethyl acid maleates are produced containing generally less than about 4 percent unreacted diethyleneglycolamide in the reaction mixture as determined by petroleum ether extraction. The acid number (mg KOH/g sample) of these acid esters will be close to acid number calculated or exceed same by about 5 to about l0 percent. The product may be further purified by extraction of the unreacted amide with low molecular weight aliphatic hydrocarbons, such as petroleum ether, to remove the unreacted amide. This will not be necessary since the unreacted amide has foam-stabilizing and thickening properties which would form a useful additive to the amidoethoxyethyl sulfosuccinate salts.

PREPARATION OF ACYLAMIDOETHOXYETHYL SULFOSUCCINATE SALTS The acylamidoethoxyethyl acid maleate is charged to a suitable reaction vessel and, if necessary, heat is applied to liquefy the reagent. [n a separate vessel, the alkali metal or a suitable alkaline earth sulfite employed as sulfonating agent is dissolved or dispersed in water. Water soluble alcohols, glycols, triols, etc. may be added as viscosity-reducing agents but are not required for the reaction. The amount of water (solvent) used may vary widely. Generally, the solutions or fluid pastes will contain upon completion from about 20 to about 40 percent by weight M.B. Active matter.

Stoichiometric amounts of alkali metal or alkaline earth sulfite or bisulfite may be used, but a moderate excess of 5 to 15 percent sulfite or bisulfite aids in producing a higher amount of MB. Active matter based on total organic solids. The sulfite solution is added to the acylamidoethoxyethyl acid maleate under agitation or the maleate may be added to the sulfite while stirring. Rate of addition is controlled to keep the temperature of the reaction mixture below about C, i.e., above about 30C and preferably about 60C. On completion of addition, which may be reversed if desired, the reaction mass is brought to about 60C and held there for 2 to 4 hours, or until the MB. Active matter has leveled off, that is, shows no further increase in concentration.

when employing sulfites, such as sodium, potassium, magnesium or mixed sulfites, such as sodium and potassium sulfite or alkali metal and tertiary amine sulfites, a neutral or midly acid pH will be encountered. Most generally, the pH will be in the range of 5 to 7. Within the pH range, the solutions may be safely heated to the preferred temperature of 60C.

When alkali metal or alkaline earth bisulfites are employed to produce half-acid sulfosuccinates, they may be later neutralized with a variety of bases. Preferably, the lowest possible temperature is chosen during the addition reaction. Thus, the use of sodium or potassium bisuifite will generally result in a pH range of 2.5 to 3 .5; and it will be desirable to keep the temperature of the reactants below about 40C during the addition and reaction cycle.

In employing the aikali metal sulfites, it is advisable that the cation be such as to result in a soluble salt of the sulfosuccinate. We prefer not to use calcium sulfite since the resultant product is not sufficiently water soluble. Magnesium sulfite has, however, been found suitable to produce the corresponding soluble salt.

The addition of bases to the acid salt for production of the neutral salt may be accompanied by adding the bases to adjust the pH to at least 5 and further heating. By this method, using ammonia or the appropriate amine, mixed salts may be obtained including such where A is ammonia, a primary, secondary or tertiary water-soluble amine.

In this connection, it should be pointed out that the addition of the sulfltes of ammonia or amines having a labile hydrogen substituent on the nitrogen atom will yield undesirable lay-products when added to the acylamidoethoxyethyl acid maleate prior to or simultaneously with the alkali metal or alkaline earth bisulfite. Similarly, the use of ammonium sulfite will result in little or no M.B. Active matter. This appears to be due to the addition of ammonia (or primary or secondary amines) to the afi-unsaturation of the maleate double bond.

The unreacted amide may be removed by extraction with a low molecular weight hydrocarbon, such as petroleum ether. Unreacted inorganic salts may be removed from the organic solids by extraction of the dried solids with alcohol, such as anhydrous ethanol. On settling, the supernatant liquid is filtered. The saltfree filtrate is diluted with deionized water and the water-alcohol solution extracted several times with a low molecular weight hydrocarbon such as petroleum ether or normal pentane. The aqueous lower layer is evaporated to remove residual solvent.

In the preferred embodiment, the process for production of acylamidoethoxyethyl sulfosuccinnate salts with unusual foaming and mildness properties may be characterized as follows:

1. Addition of maleic anhydride to acylamidoethoxyethanol at a temperature below about 70 C in order to avoid formation of undesirable maleate diesters.

2. Sulfite addition at a suitable low temperature dependent on the nature of the sulfite or bisulfite. Addition at excessively elevated temperatures materially reduces the yield of the MB. Active matter and may result in formation of gels as a result of hydrolysis of the reaction products.

3. Where sulfonates neutralized by mixed alkali metals, (or alkaline earth) and amine bases are desired, addition of the ammonia, primary or secondary watersoluble amine is preferably carried out only after preliminary reaction with the alkali metal or alkaline earth bisulfite.

4. The product produced is an acylamidoethoxyethyl sulfosuccinate in which the acyclic radical may be in the C, to C range or mixtures of such compounds in which there are mixtures of compounds containing acyclic radicals of different carbon-carbon chains, all being in the range of the C to C carbon-carbon chains.

5. The final or intermediate products may be purified to remove organic matter other than the acylamidoethoxyethyl sulfosuccinate, as the case may be, by extraction of the organic matter and the inorganic salts as described above.

The process outlined above is further demonstrated by, but not limited to the following examples:

EXAMPLE 1: COCOYLAMIDOETHOXYETHYL AClD MALEATE A 2000 ml four-neck flask equipped with a mechanical stirrer, thermometer, and condenser was charged with cocoylamidoethoxyethanol (596.6 g, 2.0 moles) prepared from coconut fatty acid and diethyleneglycolamine and having an acid number of 4.1 and free amine content of 2.35%. Maleic anhydride (199,9 g, 2.04 moles), ground into a powder for convenience of addition, was added with agitation. The reagents, while being agitated were heated by means of an external ethyleneglycol bath to 60C The reagents were completely liquefied at 50C. The reaction was mildly exothermic and the internal temperature rose to 65C. Agitation was continued while holding the temperature within the range of 6065C. The resulting monoester, a cocoylamidoethoxyethyl acid maleate had an acid number of 149.2 (theory, 146.5) and contained 1.92 percent free starting amide as determined by petroleum ether extraction.

EXAMPLE ll: COCOYLAMIDOETHOXYETHYL SULFOSUCCINATE; DlSODlUM SALT Cocoylamidoethoxyethyl acid maleate (398.3 g, 1.0 mole) from Example 1 was charged into a reaction flask equipped as in Example 1 but with an electrically heated mantle. A solution of sodium sulfite (138.6 g, 1.1 mole) in 769 g of deionized water was added over 10 minutes. The exotherm of the reaction raised the temperature from 27 to 42C in 50 minutes. The pH of the solution was found to be 5.7 and was adjusted to 6.3 by the addition of 10 ml of a 20 percent sodium hydroxide solution. Heat was then applied and the temperature of the mixture raised to 60C and held there for 4 hours. The viscous liquid was diluted to 35 percent organic solids by addition of 187 g of deionized water. The light amber liquid gave clear, foaming solutions in hard and deionized water and conformed to the following analytical values:

M.B. Active Matter (M01. Wt. 523) 26.6% Total Solids (Oven dried, C for 12 hrs) 36.5% Conversion (M.B. Actives/Organic Solids) 76.0% CCl, Soluble Matter 3.64% Color, Hellige VSC 4 EXAMPLE 111: COCOYlAMlDOETl-[YL SULFOSUCCINATE; DISODIUM SALT Cocoylmonoethanolamide (1250 g, 5.0 moles) and maleic anhydride (500 g, 5.1 moles) were reacted as described in Example 1. The resulting cocoylamidoethyl acid maleate had an acid number of 181.3 (theory, 166.7). This acid maleate 1702 g) was then reacted with 797 g of sodium sulfite (15% molar excess based upon the equivalent weight of the acid maleate) in 4344 g of deionized water according to the process conditions given in Example 11. The finished cocoylamidoethyl sulfosuccinate disodium salt conformed to the following analytical values:

MB. Active Matter (Mol. Wt. 474) 24.4% Total Solids 36.4% Conversion (M.B. Actives/Organic Solids 69.7% CCl Soluble Matter 5.94% Color, Hellige VCS 4 pH (as is) 6.38

The compound turned into a fluid, opaque paste upon standing.

EXAMPLE 1V: OLEOYLAMIDOETHOXYETHYL ACID MALEATE Oleoylamidoethoxyethanol (550 g, 1.5 mole) prepared from oleic acid and diethyleneglycolamine and having an acid number of 4.5 and free amine content of 2.5% was reacted with maleic anhydride (149.9 g, 1.53 mole) as described in Example I. The resulting acid maleate, an amber viscous liquid, had an acid value of 133.5 (theory, 125) and contained 4.31% petroleum ether soluble matter.

EXAMPLE V: OLEOYLAMIDOETHOXYETHYL SULFOSUCCINATE; DlSODlUM SALT M.B. Active Matter (Mol. Wt. 591) 29.1% Total Solids 36.6% Conversion (M.B. Actives/ Organic Solids) 83.1% CCl Soluble Matter 1.57% Color, Hellige VCS l2 pH, (as is) 6.1

EXAMPLE V1: OLEOYLAMIDOETHYL SULFOSUCCINATE; DlSODlUM SALT Oleoylmonoethanolamide (650.0 g, 2.0 moles) having an acid number of 2.4 and free amine content of 2.9% was reacted with maleic anhydride (196.0 g, 2.0 moles) as described in Example 1. After 4 hours of reaction at 60C, the acid maleate had an acid number of 143.1 (theory, 132) and contained 1.48% petroleum ether soluble matter.

One mole, 423 g, of the acid maleate was then reacted with 1.1 mole, 138.6 g, of sodium sulfite dissolved in 81 1 g of deionized water. Following a 4-hour reaction period at 60C70C, the translucent pale amber gel showed an M.B. Activity (Mol. Wt. 549) of 29.5%.

A portion of this product (548 g, 0.4 mole) was diluted with 214 g of deionized water containing 5.0 g(0.04 mole) of sodium sulfite. After heating and stirring for 2 hours at 70C, the resulting translucent solution gave the following analytical values:

MB. Active Matter (Mol. Wt. 549) 24.3% Total Solids 31.0% Conversion (M.B. Actives/Organic Solids) 81.0% CC]. Soluble Matter 6.9% pH (as is) 6.6

This compound was used to compare physical properties with that of the novel type of Example V.

EXAMPLE Vll: LAUROYLAMIDOETHOXYETHYL SULFOSUCCINATE; DlSODlUM SALT This compound was produced as shown in previous examples from 1.2 mole lauroylamidoethoxyethanol, 1.26 mole maleic anhydride, and 1.1 mole sodium sulfite. The clear solution turned opaque on cooling and gave the following analytical results:

M.B. Active Matter (Mol. Wt. 515) 34.3% Total Solids 43.1% Conversion (MB. Activies/Organic Solids) 85.7% CCI Soluble Matter 3.1% pH (as is) 5.6

EXAMPLE V111: STEAROYLAMlDOETl-[OXYETHYL SULFOSUCCINATE: DlSODlUM SALT Stearoylamidoethoxyethylmaleate (233.5 g, 0.5

mole) having an acid number of 137.8 (theory. 132.2) was prepared from stearic acid, diglycolamine, and maieic anhydride as described in previous examples. It was reacted with a solution of sodium sulfite (75.6 g, 0.6 mole) in 531 g deionized water. After 4 hours agitation at 60C, the resulting surfactant gave the following analytical values:

MB. Active Matter (Mol. Wt. 588) 27.7% Total Solids 37.16% Conversion (MB. Actives/Organic Solids) 79.1% CC], Soluble Matter 404% Color, Hellige VCS 5 pH (as is) 6.0

Physical Form Opaque Paste The compound was soluble and frothed in soft and hard water.

EXAMPLE 1X: COCOYLAMlDOETHOXYETl- YL SULFOSUCCINATE, SODIUM/TRlETHANOLAMMONlUM SALT Cocoylamidoethoxyethyl acid maleate (976.5 g, 2.464 mole) as prepared in Example 1 was reacted with sodium bisulfite (281.9 g, 2.71 mole) and triethanolamine (440.6 g, 2.957 mole) in 2,301 g of water. The reaction was carried out as previously described but at a maximum temperature of 52C and yielded a surfactant solution conforming to the following analytical values:

M.B. Active Matter (Mol. Wt. 649) 29.3% Total Solids 43.3% Conversion (M.B. Actives/Organic Solids) 73.3% CCl Soluble Matter 4.4% Color Hellige VCS 2 Viscosity at 25 C 40 cps pH (as is) 6.73

EXAMPLE X: OLEOYLAMIDOETHOXYETHYL SULFOSUCCINATE; SODlUM/AMMONlUM SALT Oleoylamidoethoxyethanol (367 g, 1.0 mole) as used in Example 1V and maleic anhydride (98 g, 1.0 mole) were reacted as described in Example IV. The acid maleate had an acid number of 131.6 (theory, 120.6) and contained 2.8 petroleum ether soluble matter.

To this maleate half ester, agitated in a 2000 m1 flask, was added sodium bisulfite (1 16.6 g, 1.1 mole) dissolved in 898 g of deionized water. Addition was completed in 5 minutes and after stirring for 1.5 hours, the temperature had risen from 20 to 3]C. The pH was adjusted from 3.1 to 3.5 by addition of 20 g of 58% ammonium hydroxide. After about 4 hours following addition of the sodium bisulfite, additional 58% ammonium hydroxide (60.7 g, 1.0 mole) was added to the reaction mass, giving a pH of 6.35. The solution was then heated to 60C. After 1.5 hours at 60C, the solution contained 29.2% MB. Active matter and remained at this level of activity after an additional two hours at this temperature. The final product had the following analysis:

M.B. Active Matter (Mol. Wt. 586) 29.3% Total Solids 41.5% Conversion (M.B. Actives/Organic Solids) 73.3% Color, Hellige VCS 1 Physical Form Fluid Paste EXAMPLE Xl: COCOYLAMIDOETHOXYETHYL SULFOSUCCINATE; MAGNESIUM SALT M.B. Active Matter (Mol. Wt. 500.6) 22.8% Total Solids 32.5% Conversion (MB. Actives/Organic Solids) 76.0% CC]. Soluble Matter 1.74% Color. Hellige 1 pH (as is) 5.35

Physical Form Clear Solution EXAMPLE Xll: OLEOYLAMIDOETHOXYETHYL SULFOSUCCINATE; Dl AMMONlUM SALT Oleoylamidoethoxyethyl maleate (1.0 mole, 470 g) was agitated while adding ammonium sulfite monohydrate (1.1 mole, 147.6 g) dissolved in deionized water (1056 g). No exothermic reaction was noted and the viscosity of the dispersion increased to form a gel. On adjusting the pH to 6.5 with ammonium hydroxide (42 g, 58%) temperature was raised to 60C and held there for 5 hours. Samples were taken after one, two and five hours at this temperature and showed zero MB. Activity. The resulting pasty product was dispersible in water to form hazy solutions. lt is believed that the failure to produce the desired sulfosuccinate stems from the competitive reactivity of ammonia with the a,B-unsaturation of the maleate radical.

EXAMPLE Xlll: COCOYLAMlDO-N-HYDROXYETHYL-N-ETHYL SULFOSUCCINATE, D1 SODIUM SALT o cn ca 0 c n a 2 2 a q C 2 C-0 Na Idealized formula.

This preparation was carried out to determine a possible equivalence of diethanolamide derivatives to diglycolamide derived sulfosuccinates; Cocoylamido-N- hydroxyethyl-N-ethylmaleate was prepared by reacting Cocoyldiethanolamide (acid No. nil; free DEA 7.05%: Ester content 0.8%; M01. Wt. 292) 1.5 mole, with 1.53 mole of maleic anhydride as in previous examples. One

mole (392.0 g) of this acid maleate, having an acid number of 167.3 was reacted with 1.15 mole (144.9 g) of sodium sulfite, dissolved in 758 g deionized water. The exotherm raised the temperature to 43C and heat was applied to bring the temperature to C. After 4 hours at this temperature, the compound showed an M.B. activity of only 17.4% on 43.3% total solids. Conversion based on organic solids was only 40.2%. The solution separated into two layers on standing. A product of such low activity would not be suitable for the purposes indicated in this specification.

EXAMPLE XIV: COCOYLAMIDOETHOXYETHYL SULFOSUCCINATE; CALCIUM SALT Cocoylamidoethoxyethylmaleate 1.0 mole, 396.3 g) was agitated while adding a dispersion of calcium sulfite dihydrate (1.1 mole, 171.8 g) in deionized water (1153 g). The calcium sulfite dispersion showed a pH of 8.9 and the reaction mixture following addition gave a pH of 3.3. The pH was raised to 4.5 by addition of 21 ml of 50% NaOH solution, and the temperature was brought to 60C. The M.B. activity rose very slowly from 4.93% after 1 hour to 8.29% after 5 hours, corresponding to a conversion of only 27.6% based on organic solids. The solution separated on standing. lnsol' ubility of the calcium salt appears to be the cause of the failure observed.

While for the purposes of use as a frothing agent in bubble bath formulations, hair shampoos, and in liquid and bar soaps, the level of organic compounds other than the compounds of our invention is satisfactorily low as explained above, the acylamidoethoxyethyl sulfosuccinates which are the products of the above examples may be further purified to remove the unreacted reactant components at each stage as set forth above.

The water solutions formed in the above examples may be dried to give the solid succinate salt containing low levels of the precursors. They may be made substantially free of the aforesaid precursors and inorganic salts, by following the purification procedures described above.

As was pointed out above, the addition of the bisulfite forms the half-acid sulfosuccinate salt. Further neutralization forms the neutral salt. The corresponding acid may be formed by acidifying the salt as will be understood by those skilled in the art.

The foaming properties of the sulfosuccinate salts of our invention as compared with the corresponding salts of the prior art are tabulated in Table l. The Ross-Miles pour foam numbers were determined by the test described in Oil and Soap 18, 99-102 (1941). 1n this test, a sample of the solution containing the surfactant is discharged from a container through an orifice to fall through a prescribed height into a pool of like solution.

The results of the test (see Table 1) indicate an excellent production of a stable foam in both soft and hard waters.

Table l Ross-Miles Pour Foam Numbers. expressed in mm foam height at 25 C, 0.2% solutions based on organic solids -amidoethoxyethyl- Cations Deionized Water Hard Water [250 ppm) sulfosuecinate, 0 seconds 60 seconds 300 seconds 0 seconds 60 seconds 300 seconds Oleoyl Na/Na 180 153 187 161 160 Oleoyl Nat/TEA 195 167 I75 155 152 Cocoyl Na/Na 200 170 169 205 182 Cocoyl Nal'I'EA 217 174 171 199 177 169 Cocoyl Mg/Mg 199 178 174 204 182 178 Cocoyl Nat/NH, 194 171 168 202 183 177 (See above examples) 'Triethanolamine W,=reflectance value of white portion after laundering.

S qeflectance value of soiled portion after laundering.

Table IV gives the comparative value of a standard detergent and the compounds of the prior art which do not contain the bridging ethoxy group and the compounds of our invention which have the same acyl group.

TABLE ll WASH TEST ON STANDARD WOOL SOIL CLOTHS Compound (0.25% solids basis) Anions Detergency Efficiency whiteness Retention Sodium Lauryl Sulfate Na 94 99 Cocoylamidoethyl Sulfosuccinate Na/Na 90 98 Oleoylamidoethyl Sulfosuccinate Na/Na 96 98 Cocoylamidoethoxyethyl Sulfosuccinate Na/Na 50 98 Oleoylamidoethoxyethyl Sulfosuccinate Na/Na 60 99 "See above Examples of our Invention.

whiteness retention R is defined:

R W XlOO Where W=the reflectance value of the white portion before laundering, S=reflectance value of the soiled portion before laundering.

It will be observed that the compounds of our invention have much lower detergency efficiency. This is be cause they have much lower emulsifying power for the natural oils of the wool and for oily soil.

This is also illustrated by the higher interfacial tension against corn oil of the acylamidoethoxyethyl sulfosuccinate compared with the acylamidoethyl sulfosuccinate having the same acyl radical and cations. See Table ll.

As noted in the case of the cocoylamidoethoxyethyl sulfosuccinate disodium salt (Example II), the oleoylamidoethoxyethyl sulfosuccinate disodium salt of Example V also gave rise to much lower defatting properties than the analogous compound prepared from oleoylmonoethanolamide as indicated by the higher surface and interfacial tension values and lower oily soil extraction from the wool fabric in the detergency test (see Tables ll, lll, and IV). Yet, these compounds have a comparable level of froth-forming properties.

Parallel to this observation are the higher interfacial and surface tension values and reduced oily soil removal obtained with the products of this invention as compared to the products of the prior art as shown in Tables II, III and IV.

TABLE Ill Surface Tension, Du Nuoy, expressed in dynes/cm at 25 C for 0.1% solutions based on organic solios -amidoethoxyethylsulfosuccinate,* Cations Deionized Water Hard Water (250 ppm) Oleoyl Nit/Na 32.4 34.7 Oleoyl Nafl'EA" 20.5 32.1 Cocoyl Na/Na 30.8 32.3 Cocoyl Na/TEA" 32.5 32.2 Cocoyl Mg/Mg 32.4 32.2 Cocoyl Nat/NH 32.2 32.l -amidoethylsulfosuccinate,'

Oleoyl Na/Na 30.8 3 Li Cocoyl Na/Na 30.2 30.7

TABLE IV lnterfacial Tension, Du Nuoy, expressed in dynes/cm at 25 C for 0.1% solutions based on organic solids measured against Corn Oil -amidoethoxyethylsulfosuccinate,

Oleoyl Cocoyl -amidoethylsulfosuccinate Oleoyl Cocoyl See the above Examples.

the physiological mildness of the sulfosuccinates of our invention is illustrated by the following data employing the product of Example V.

This compound produced 0.0 exposure unit values of skin irritation at concentrations of 0.25%, 1.0% and 5.0% based on organic solids. All products producing irritation indices of 5.0 or more are classified as primary irritants under the protocols of the Hazardous Substances Labeling Act of 1960, when tested as described in Section l9l.l-Part 1.

Similarly, a 0.0 score was obtained when this compound was subjected to the Draize Eye Test at a concentration of 5.0% based on organic solids. The compound of Example [X produced 0.0 exposure unit values of skin irritation at concentrations of 5.0%, 10.0% and 40% and gave an 0.0 score in the Draize Eye Test at concentrations of 5.0% and 10.0% based on organic solids. Draize irritation indices are calculated for each sample for each concentration employed. The highest index possible for this method of evaluation is 1.0, indicating a severe eye irritant, often producing permanent eye injury.

A 5.0% solution (based on organic solids) of cocoylamidoethyl sulfosuccinate, disodium salt, for example, as described in German Pat. No. 1,1 15,398 and prepared in Example [11 above, resulted in an irritation index of 0.66 of the conjunctivae in 24 hours.

The above mildness is characteristic of the sulfosuccinates of our invention. The introduction of a single ethylene glycol linkage between the amidoethyl group and the sulfosuccinate group results in a surfactant which is non-irritating to the eye, while in the absence of such a linking group, marked irritation to the cunjunctivae was noted.

it is believed that the higher surface and interfacial tension values result in reduced defatting action of the surfactants of this disclosure and contribute to their mildness to eyes and skin. While inferior detergents (Table 11), they are, nonetheless, excellent froth formers (Table l) and lend themselves ideally as hair shampoos, bubble bath compounds, and synthetic liquid or bar soaps.

The above sulfosuccinate salts have particular utility in formulating the bubble-bath formulations, hair shampoos, and synthetic liquid or bar soaps in which they may be used alone as the froth-forming agent or as supplement and diluent to detergents to modify the defatting properties of the detergents.

The addition of from 250% of the sulfosuccinate salts of our invention to soap formula to replace an equal amount of soap will give a useful soap which will not unduly remove natural oils from the hair or body portions. Reference may be had to the aforementioned U.S. Pat. No. 3,280,179, col. 28, for description of the content of standard soap formulations. A practical range for bar soaps is about 5% to 30% by weight of the sulfosuccinate salt of our invention.

The dried reaction product of the above examples may be used directly as a solid frothing agent without admixture with soaps as above.

The low defatting properties and high frothing action of the sulfosuccinate salts of our invention make them highly useful compounds for hair shampoos. The anionic surfactants commonly used in shampoos act to defat the hair and to make the hair brittle and to cause the hair to tangle and snarl. This property is termed harshness." The compounds of our invention when used in shampoos will avoid the necessity of cationic rinses and other hair conditioners.

A primary consideration is the mildness of the frothers of our invention, as compared with the detergents employed in the prior art. The sulfosuccinates of our invention may be used in place of or to supplement other surfactants in conventional hair shampoo (liquid, creme lotion, creme paste) formulations (see U.S. Pat. No. 3,280,179, col. 32 et seq). The sulfosuccinate salts of our invention may be used in place of or as supplements to the surfactants referred to in the patent or in the literature references cited therein.

For purposes of illustration and not as a limitation, a shampoo base employing the sulfosuccinate salts of our invention may have the following formulation:

098% IOU-2% Anionics Aforementioned sulfosuccinate salts where R is an alkyl or an alkenyl group having from 7-19 carbon atoms in an uninterrupted carbon-carbon chain, M may be an alkali metal or alkaline earth cation which results in a soluble salt, A may be M or ammonia or a water soluble salt forming amine, or H.

2. The compound of claim 1 in which RC0 is cocoyl or tallowyl or oleoyl.

3. The compound of claim 1 in which R is C, to C and RC0 is an acyl radical present in at least one of the cocoyl or one of the tallowyl or one of the oleoyl compounds having the aforesaid constitutional formula.

4. The compound of claim 1 in which R is in the range of C to C and in which the RC0 radical is cocoyl or tallowyl or oleoyl.

5. A composition of matter consisting essentially of a mixture of from about 60 to about of acylamidoethoxyethyl succinate salts and from about 40 to about 15% of acylamidoethoxyethanol or an acylamidoethoxyethyl maleate having the acyl radical of said acylamidoethoxyethanol or mixtures thereof.

6. 1n the composition of claim 5 in which the acyl radical is cocoyl or tallowyl or oleoyl.

7. The process which includes:

A. the step of mixing maleic anhydride with acylamidoethoxyethanol at a temperature within the range of about 15 to about 70C for a period of time to permit the reaction of said maleic anhydride and said acylamidoethoxyethanol, the amount of said maleic anhydride being from about 1 to about 1.! times the stoichiometric amount of the aforesaid acylamidoethoxyethanol, the acyl radicals of said acylamidoethoxyethanol being RCO where R is from C to C or a mixture within the range C to C and thereby forming acylamidoethoxyethyl maleate and B. the step of reacting the acylamidoethoxyethyl maleate with from about 5 to about 15 percent excess of a sulfite or a bisulfite chosen from the sulfites and bisulfites having cations to produce water soluble salts of acylamidoethoxyethyl sulfosuccinates in which the acyl radical is as defined in A above, and thereby forming a water soluble acylamidoethoxyethyl sulfosuccinate salt.

8. The process for production of an acylamidoethoxyethyl sulfosuccinate neutral salt in which the acyl radical RC is one where R is C, to C or is a mixture coming within the range of C to C and in which the cations of the salt are an alkali metal, or an alkaline earth cation which yields a water soluble sulfosuccinate salt or said metallic cations mixed with a tertiary amine, including:

A. the step of forming an acylamidoethoxyethyl maleate by reacting maleic anhydride with acylamidoethoxy ethanol by mixing the aforesaid compounds at a temperature within the range of about 15 to about 70C, the amount of said maleic anhydride being from about 1 to about 1.1 times the stoichiometric amount of the acylamidoethoxyethanol and B. the step of reacting at a temperature from about 70 to above about 30C, the aforesaid acylamidoethoxyethyl maleate with from about 5 to about 15 percent excess of alkali metal sulfite or alkaline earth sulfite or alkali metal sulfite and a tertiary amine to form the soluble salts of the aforesaid acylamidoethoxyethyl sulfosuccinate.

9. The process for producing the acid salt of an acylamidoethoxyethyl sulfosuccinate in which the acyl radical RC0 is one where R is C to C or is a mixture coming within the range of C to C and in which one of the cations of the salt is an alkali metal, or a water soluble salt yielding alkaline earth metal, including:

A. the step of forming an acylamidoethoxyethylmaleate by reacting maleic anhydride with acylamidoethoxyethanol by mixing the aforesaid compounds at a temperature within the range of about l5 to about C, the amount of said maleic anhydride being from about I to about Ll times the stoichiometric amount of the acylamidoethoxyethanol and B. the step of reacting at a temperature from about 70 to above about 30C, the aforesaid acylamidoethoxyethyl maleate with from about 5 to about 15 percent excess of alkali metal bisulfite or an alkaline earth bisulfite having cations to form a water soluble acid salt of the aforesaid acyclamidoethoxyethyl sulfosuccinate or mixtures of said bisulfites.

10. [n the process of claim 9, neutralizing the said acid salt with a base by adding said base while maintaining said reaction mixture during said addition at a temperature below about 40C.

11. In the process of claim 10, heating said mixture after addition when the pH has risen to at least 5 to complete said reaction.

12. The process of claim 11 separating the acylamidoethoxyethyl sulfosuccinate salt from the in organic material by extracting the neutralized product with a water-alcohol solution and extracting said wateralcohol solution with a low molecular weight hydrocarbon and evaporating the solvent.

UNITED STATES PATENT OFFICE Patent No.

Dated June 24 1975 I ROBERT ERNST and EUGENE J. MILLER It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

1. Column 1,

2. Column 2,

3. Column 2,

4. Column 2,

5. Column 5,

6. Column 6,

7. Column 6,

8. Column 8,

9. Column 12,

10. Column 11,

ll. Column l3,

l2. Column 13,

[SEAL] line 16, correct the spelling of (n-9-octadecemoyl) to (n-9-octadecenoyl) line 27, change "coil" to oil line 52, before "is," change "a" to A line 28, after "70" insert line 1, after "C" insert before "The."

37, correct the spelling of, "COCOYIAMIDOETHYL" t0 COCOYLAMIDOE'IHYL line line 53, insert then before "adjusted."

line 47 of the table, change "solios" to solids insert another-line which Triethanol amine after the last line,

reads insert as line 39, after "inferior,

Signed and Sealed this thirtieth D ay Of September I 9 75 Anesr:

RUTH C. MASON Auemng Officer C. MARSHALL DANN (mmmsnunvr nr lau'nlx and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,891,682 Dated June 24, 1975 Inventor(s) ROBERT ERNST and EUGENE J. MILLER It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

line 29, change "Table 'II" to Table IV Signed and Scaled this second D 3) or December 19 75 13. Column 12,

[SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN l lrrl'sling Officer Commissioner uj'Parents and Trademarks Disclaimer and Dedication 3,891,682.-R0bert Ernst, Los Angeles, and Eugene J. Miller, Huntington Beach, Calif. AOYLAMIDOETHOXYETHYL SULFOSUOOI- NATE SALTS, METHODS OF PRODUCING THE SAME AND FROTH-FORMING COMPOSITIONS CONTAINING THE SAME. Patent dated June 24, 1975. Disclaimer and dedication filed May 11, 1976, by the assignee, H enkel Inc.

Hereby disclaims and dedicates to the Public the remaining term of said patent.

[Official Gazette July 20, 1976.1 

1. A COMPOUND HAVING THE CONSTITUTIONAL FORMULA
 2. The compound of claim 1 in which RCO is cocoyl or tallowyl or oleoyl.
 3. The compound of claim 1 in which R is C7 to C19 and RCO is an acyl radical present in at least one of the cocoyl or one of the tallowyl or one of the oleoyl compounds having the aforesaid constitutional formula.
 4. The compound of claim 1 in which R is in the range of C7 to C19 and in which the RCO radical is cocoyl or tallowyl or oleoyl.
 5. A composition of matter consisting essentially of a mixture oF from about 60 to about 85% of acylamidoethoxyethyl succinate salts and from about 40 to about 15% of acylamidoethoxyethanol or an acylamidoethoxyethyl maleate having the acyl radical of said acylamidoethoxyethanol or mixtures thereof.
 6. In the composition of claim 5 in which the acyl radical is cocoyl or tallowyl or oleoyl.
 7. The process which includes: A. the step of mixing maleic anhydride with acylamidoethoxyethanol at a temperature within the range of about 15* to about 70*C for a period of time to permit the reaction of said maleic anhydride and said acylamidoethoxyethanol, the amount of said maleic anhydride being from about 1 to about 1.1 times the stoichiometric amount of the aforesaid acylamidoethoxyethanol, the acyl radicals of said acylamidoethoxyethanol being RCO where R is from C7 to C19 or a mixture within the range C7 to C19 and thereby forming acylamidoethoxyethyl maleate and B. the step of reacting the acylamidoethoxyethyl maleate with from about 5 to about 15 percent excess of a sulfite or a bisulfite chosen from the sulfites and bisulfites having cations to produce water soluble salts of acylamidoethoxyethyl sulfosuccinates in which the acyl radical is as defined in A above, and thereby forming a water soluble acylamidoethoxyethyl sulfosuccinate salt.
 8. The process for production of an acylamidoethoxyethyl sulfosuccinate neutral salt in which the acyl radical RCO is one where R is C7 to C19 or is a mixture coming within the range of C7 to C19 and in which the cations of the salt are an alkali metal, or an alkaline earth cation which yields a water soluble sulfosuccinate salt or said metallic cations mixed with a tertiary amine, including: A. the step of forming an acylamidoethoxyethyl maleate by reacting maleic anhydride with acylamidoethoxy ethanol by mixing the aforesaid compounds at a temperature within the range of about 15* to about 70*C, the amount of said maleic anhydride being from about 1 to about 1.1 times the stoichiometric amount of the acylamidoethoxyethanol and B. the step of reacting at a temperature from about 70* to above about 30*C, the aforesaid acylamidoethoxyethyl maleate with from about 5 to about 15 percent excess of alkali metal sulfite or alkaline earth sulfite or alkali metal sulfite and a tertiary amine to form the soluble salts of the aforesaid acylamidoethoxyethyl sulfosuccinate.
 9. The process for producing the acid salt of an acylamidoethoxyethyl sulfosuccinate in which the acyl radical RCO is one where R is C7 to C19 or is a mixture coming within the range of C7 to C19 and in which one of the cations of the salt is an alkali metal, or a water soluble salt yielding alkaline earth metal, including: A. the step of forming an acylamidoethoxyethylmaleate by reacting maleic anhydride with acylamidoethoxyethanol by mixing the aforesaid compounds at a temperature within the range of about 15* to about 70*C, the amount of said maleic anhydride being from about 1 to about 1.1 times the stoichiometric amount of the acylamidoethoxyethanol and B. the step of reacting at a temperature from about 70* to above about 30*C, the aforesaid acylamidoethoxyethyl maleate with from about 5 to about 15 percent excess of alkali metal bisulfite or an alkaline earth bisulfite having cations to form a water soluble acid salt of the aforesaid acyclamidoethoxyethyl sulfosuccinate or mixtures of said bisulfites.
 10. In the process of claim 9, neutralizing the said acid salt with a base by adding said base while maintaining said reaction mixture during said addition at a temperature below about 40*C.
 11. In the process of claim 10, heating said mixture after addItion when the pH has risen to at least 5 to complete said reaction.
 12. The process of claim 11 separating the acylamidoethoxyethyl sulfosuccinate salt from the inorganic material by extracting the neutralized product with a water-alcohol solution and extracting said water-alcohol solution with a low molecular weight hydrocarbon and evaporating the solvent. 